WO1994022387A1

WO1994022387A1 - Elbow for dental tool-holder

Info

Publication number: WO1994022387A1
Application number: PCT/EP1994/001059
Authority: WO
Inventors: Alfred Leiter
Original assignee: Janert, Rolf; Riesch, Hans-Curt
Priority date: 1993-04-05
Filing date: 1994-04-05
Publication date: 1994-10-13
Also published as: ATE149322T1; EP0693907B1; EP0693907A1

Abstract

An elbow useful in dentistry has a housing (1) which consists of a head (3) and a shaft (2). A rotary driven clamping device (6) housed in the head (3) is used for clamping a tool (29) which is introduced from the front side of the head (3) into the clamping device (6). A push-button provided on the rear side of the head (3) acts on the clamping device (6), opening it when the pushbutton (15) is pressed. A cooling fluid duct (14, 14a, 19, 20, 23) is arranged in the shaft (2) and the head (3) and opens into the head (3). The tool (29) has a longitudinal throughbore (30), the duct (20, 23) extends through the intermediate space (23) of the two-piece pushbutton (15) and opens from behind into the bore (30) of the tool (29).

Description

Contra-angle handpiece for dental needs

Description:

The invention relates to an elbow with the features specified in the preamble of claim 1. The dentist needs such contra-angles for drilling, grinding and milling work on teeth and jawbones. The angle piece contains gear elements for the rotary drive of a clamping device, which is arranged in the head part of the angle piece and is used for clamping the tool. It is known to design the clamping device as a collet in which

0RIG1NAL DOCUMENTS rather the tool is fixed by spring force. It is also known to actuate the collet by a push button provided on the back of the head part; for this purpose, a displaceable sleeve is provided between the push button and the collet, which engages with its wedge-shaped front end in the collet and expands it when the push button is depressed.

In the case of jaw surgery work in particular, it is important to ensure that the tool does not become too hot, because at temperatures from approximately 40-42 ° C. the bone tissue begins to die and implants no longer grow in. The known elbow therefore has an annular cover on the front of the head part with one, two or three nozzles, to which water is supplied through a feed line running in the shaft part of the elbow, which water is sprayed against the tool from the outside through the nozzles.

However, tools that are cooled from the inside and have a longitudinally continuous bore for this purpose enable more effective cooling. Tools cooled on the inside have the advantage over tools cooled on the outside that they only spin off a little water, as a result of which germs can be distributed in the mouth and outside the mouth, which the dentist and his auxiliary personnel have to breathe in.

It is known to supply the water to cooled tools by means of a hose running from the rear is brought into the head part of the contra-angle. The disadvantage here is that the hose leading out of the back of the head part is a hindrance when working in the mouth and that the tensioning device cannot be actuated by a push button; it is rather known in this case to provide a collet which can be opened and closed by means of a pivoting lever. The hose ends in the elbow on a tube over which the pierced tool with its hole must be pushed when the tool is in the

Angle piece is used. Since the tool is very thin in any case, inserting and threading the tool onto the cooling water tube with the open collet is very laborious.

An angle piece with the features given in the preamble of claim 1 is known from EP-A-374 276. It is used to hold a longitudinally pierced tool, to which the cooling water is fed through a supply line running in a push button; the push button has a central extension which is opposite the rear end of the tool. The supply line runs completely inside the contra-angle handpiece, but this is purchased with considerable structural and sealing effort.

The present invention has for its object to provide an angle piece which with internally cooled work witness can be operated, but is as simple as possible to use and set up.

This object is achieved by an elbow with the features specified in claim 1. Advantageous developments of the invention are the subject of the dependent claims.

The solution according to the invention is surprisingly simple. This is achieved in that the coolant is fed to the tool through the space between the lower part and the upper part of a two-part push button, to which a multiple function is assigned in this way, namely to actuate the clamping device, a line connection to the rear end of the tool to manufacture, thereby tightly sealing the housing from the outside and closing the interior of the head part against the feed line section running in the space between the push button. A sliding guide, sealed by an O-ring, between the push button and the housing, as known from EP-A-374 276, is not necessary. Rather, the push button can be a simple, flat plastic part which encloses the housing on the back in the manner of a cap hermetically seals. This improves the sealing on the one hand and simplifies production and assembly on the other. Despite the smallness of the contra-angle handpiece and the push button, which is unavoidable due to the dental purpose, it is possible to lead the coolant supply in the button part through the gap between the push button, because with the required coolant quantities of less than 50 ml / min. can be worked with small wire cross-sections. The result is a contra-angle handpiece that can look like the known contra-angle handpiece with an externally cooled tool, but in which no hose on the head part interferes with the dental work and in which a tool change is possible simply by pressing the push button on the back .

On its underside, the push button preferably has an extension which is in alignment with the tensioning device and through which the supply line for the coolant passes. In order to establish a line connection with the tool, when the tool is inserted the extension extends into the bore of the tool or the tool extends with its rear end into the

Extension into it so that either the tool surrounds the extension or the extension surrounds the tool in the manner of a sleeve. Since the extension is in alignment with the clamping device, the rear end of the tool can easily be threaded onto the extension of the push button, because the clamping device guides the tool directly into alignment with the extension, during insertion

of the tool by reducing the pressure exerted on the push button with the thumb of the hand holding the handpiece, the collet can be closed to such an extent that the tool can be inserted almost without play, whereby it centers in the desired manner on the extension becomes.

In order to achieve the necessary tightness of the line connection, one can simply ensure a sufficiently long overlap of extension and tool; to do this either

Tool bored from the rear end to the appropriate length to accommodate the extension in the desired length, or the extension has an enlarged inner diameter of the appropriate length to accommodate the rear end of the tool in the desired length. Sufficient tightness can also be achieved with a shorter overlap of extension and tool if, in the event that the extension is inserted into the bore of the tool, the extension is provided on the outside with a bead at its front end, whose outside diameter is machined to fit the hole in the tool; In the event that the tool is to be inserted into the extension with its rear end, the same can be achieved by providing a recess on the outside at the rear end of the tool, into which a suitable recess formed on the inside of the extension is provided The projection engages and thereby tightly encloses the tool. There may and should be play in the longitudinal direction of the extension between the extension and the tool in order to ensure that the clamping device can be loosened effortlessly despite the intermeshing of the extension and the tool.

The push button expediently consists of thermoplastic plastic, which can be metalized on the outside. This not only has the advantage that it can be easily pressed, screwed or glued into the housing of the contra-angle handpiece, but also that it does not have to be movably mounted as a whole, but rather the pressure actuation by deflecting a thinner, yielding middle part of the Push button can be effected. In this case, it is advantageous to insert a protruding metal tube into the extension of the push button for reasons of stability and dimensional accuracy, which can be glued or injected or pressed in.

The thermoplastic push button is formed in two parts and accordingly consists of a lower part fastened in the housing and an upper part, which can also be fastened directly in the housing, but preferably fastened in the lower part, for example glued to the edge, in particular pressed in. With such a two-part push button you can see the section of the feed line that passes through it Realize particularly easy for the coolant by letting it run between the lower part and the upper part, from where it leaves the push button through the middle of the lower part through its extension. At the same time, enough flexibility for the push button function is achieved without difficulty. However, the push button could also be made of metal if it is ensured by means of a sufficiently thin wall that it can be deflected like a membrane.

At which point the supply line can be let out of the housing of the contra-angle handpiece and enter the push button is influenced by the construction of the contra-angle handpiece in its conventional parts. The simplest way is to arrange the supply line so that it crosses the edge area of the lower part. Preferably, the shape of the lower part of the push button and the housing opening into which the push button is inserted are matched to one another in such a way that an annular channel is provided between the lower part and the housing of the elbow, which is part of the feed line. This has the advantage, on the one hand, that when inserting the push button into the housing, one does not have to pay attention to a specific orientation in order to bring the inlet cross section of the feed line running in the lower part of the push button into alignment with the outlet cross section of the feed line running in the housing, and has to Another advantage is that several branch lines can lead from this ring channel into the space between the lower part and the upper part of the push button, each of which has a small clear cross-section in itself, but taken together, however, allows a sufficient amount of coolant to pass through. In the case of contra-angle handpieces with a very small head, however, it may be more advantageous to dispense with the ring channel for space reasons.

In principle it is sufficient if the upper part is only fixed at the edge; If you press on the upper part, then depending on the distance between the upper part and the lower part, you first have an idle stroke until the lower part can be deflected and in turn acts on the clamping device. However, the empty stroke is preferably avoided by providing one or more feet in the vicinity of the extension of the lower part, by means of which the upper part is supported on the lower part. The feet can either be attached to the upper part or the lower part. They are in the supply line without blocking the flow path.

A further advantage of the invention lies in the fact that, in an angle piece designed according to the invention, not only tools to be cooled from the inside but also tools to be cooled from the outside can be used, it is even possible to combine the internal cooling and the external cooling in combination Bring application and thereby make the cooling particularly effective. All that is required is Assign one or more ^* nozzles for external cooling of the tool on the side of the head part in a manner known per se and to supply them either with a separate supply line running in the angle piece or the nozzles and the hollow tool with a common supply line branching in the angle piece to feed with the coolant, the latter option being the simpler, whereas the first option has the advantage that the internal cooling and external cooling can be switched on and off as desired.

Water is usually used as the cooling liquid, but the contra-angle handpiece - if medically indicated - can also be operated with other cooling liquids als or with compressed air as the coolant

Claim generally the term cooling fluid was used.

A further advantageous development of the invention consists in that, in the case of an angle piece, which in addition to a water supply line also has a compressed air supply line in a known manner, the sealing gap at the transition from the push button to the clamping device or to the tool is provided by a compressed air branch line leading there is placed under increased external pressure and thereby prevents water leakage without contact. A corresponding one can be used for angle pieces without compressed air supply Achieve the result if the transition from the push button to the tool is designed as a water jet pump, the suction side of which is connected to the sealing gap.

Embodiments of the invention are shown in the accompanying drawings. The same or corresponding parts are denoted in the various exemplary embodiments with the same reference numbers.

Figure 1 shows schematically a first elbow in

Longitudinal section, in approximately 10 times magnification,

FIG. 2 shows as a detail from FIG. 1 the lower part of the push button and its connection with a tool, the whole in longitudinal section,

FIG. 3 is a detailed illustration like FIG. 2, but with a modified lower part,

FIG. 4 is a detailed drawing like FIG. 2, but with a further modified lower part and with a modified tool,

FIG. 5 is a detailed drawing like FIG. 2 with the lower part and tool modified again. FIG. 6 is a detailed drawing like FIG. 2, but with a modified lower part of the push button and a modified tool,

FIG. 7 shows the push button from FIG. 6 inserted in an angle piece in longitudinal section,

FIG. 8 shows, very schematically, an angle piece with the possibility of internal cooling and external cooling, both of which are supplied via a common supply line,

Figure 9 shows very schematically in longitudinal section another angle piece with the possibility of internal cooling and external cooling of the

Tools that are fed by a common, branching supply line,

Figure 10 shows another angle piece schematically in longitudinal section, with the possibility of

Air pressure on the sealing gap,

Figure 11 shows the cross section XI-XI according to Figure 10, and

FIG. 12 shows the cross section XII-XII according to FIG. 10

Identical or corresponding parts are identified in the examples with matching reference numbers.

The angle piece shown in FIG. 1 has a housing 1, consisting of a shaft part 2 and a head part 3, which enclose a right angle with one another with their gear axes 4 and 5. A collet 6 is rotatably mounted in the head part 3 via a ball bearing 7. A wedge-shaped sleeve 8 engages in the wedge-shaped opening fingers 6a and is rotatably mounted in the head part via a ball bearing 9. The collet 6 is driven by a shaft 10 and gear wheels 11 and 12 mounted in the shaft part 2.

In the shaft part 2 of the housing there is a shaft 13 which protrudes rearward from the housing and serves to insert the angle piece into an associated handle (not shown). Two supply lines 14 and 45 run lengthwise in the shaft, one of which leads into a push button 15 via a section 14a running in the housing wall, which closes the rear side (upper side) of the head part 3. The push button is injection molded from thermoplastic material and consists of a lower part 16 and an upper part 17. The lower part 16 has an outer winch 18, with which it is screwed into the rear housing opening in the head part 3. Below the thread 18, the outer diameter of the lower part 16 is reduced, as a result of which an annular channel 19 is formed between the lower part 16 and the housing, in which the section 14a

Lead 14 opens. From this ring channel, a plurality of stub lines 20 run parallel to the axis 5 through the lower part 16 on its upper side, which is framed by a raised edge 21, in which the upper part has a slight undercut on a step 22

17 is pressed in, a chamber 23 remaining between the upper part and lower part, which is a continuation of the channel 14. The upper part 17 is supported on the lower part 16 via an extension, formed by two feet 24, which are not arranged far from the axis 5. Both the lower part and the upper part have a section 25 or 26 with only a thin wall thickness between their edge section and their central section, as a result of which the push button 15 becomes so flexible that the printing function can be easily carried out. The lower part 16 has in the middle an extension 27 projecting downwards, into which a metal sleeve 28 is inserted, which projects downward from the plastic extension 27.

The sleeve 28 is inserted with its protruding section in the bore of a tool 29 which is drilled along its entire length and which is fixed in the collet 6. For this purpose, the bore 30 of the tool is in the rear Drilled section of the tool to make it possible that the inner diameter of the sleeve 28 is the same as the inner diameter of the bore 30 in the front section of the tool 29. Between the sleeve 28 and the tool 29 and between the extension 27 and the tensioning device 8 is an elongated annular gap 28a, which the water can hardly overcome.

Through the supply line 14, 14a, through the ring channel 19, the branch lines 20 and the chamber 23, cooling liquid can penetrate through the outlet 44 into the sleeve 28 and from there into the bore 30 of the tool 29.

A shoulder of the lower part 16 adjoining the extension 27 bears against the rear of the sleeve 8. As a result, when the push button is depressed, the sleeve 8 is pressed with its wedge-shaped tip between the fingers 6a of the collet and spreads it a little, whereby the tool 29 is released and can be pulled out for exchange.

The second feed line 45 opens via a section 15a running in the housing wall into an annular channel 31 which feeds a plurality of nozzles 32 directed towards the outside of the tool 29.

The transition from the feed lines 14 and 45 to their sections 14a and 45a is sealed by O-rings 33 and 34. The lower part 16 of the push button shown in FIG. 3 differs from the lower part shown in FIG. 1 and FIG. 2 in that the metal tube 28, which is inserted into the plastic extension 27, has a "flange that is not encapsulated by the plastic, but lies in a recess on the upper side of the lower part and is pressed or glued in. Furthermore, this lower part differs from that from FIG. 1 in that it does not have an external thread, but instead has an outwardly projecting bead 35 with which it is pressed into the rear opening of the head part 3.

The lower part shown in FIG. 4 differs from that shown in FIG. 2 in that instead of the metal tube 28, the extension 27 made of plastic is extended and has a further extension 27a with a reduced diameter, so that it extends into the drilled rear end of the tool 29 fits.

The lower part of the push button shown in FIG. 5 differs from that in FIG. 4 in that the extension 27a has an outer annular bead 27b at the lower end, which is dimensioned such that it fits in the drilled end of the tool 29 and thereby seals the connection well. The embodiment shown in FIG. 6 differs from that shown in FIG. 5 in that the tool 29 is twisted off at the rear end and shaped into a nipple 36 with an undercut 37. The nipple 36 is inserted in the lower end of the extension 27, which is designed with a corresponding inner contour and an inward-pointing projection 38, which is designed there with such a small wall thickness that it can be pushed onto the nipple 36 without slitting and elastically widening thereby creating a tight connection.

FIG. 7 shows the push button shown in FIG. 6 installed in the housing from FIG. 1.

The embodiment shown in Figure 8 is particularly suitable for an elbow with a turbine drive. The drive elements including the tensioning device are not shown for reasons of clarity. The lower part of the push button differs from that from FIG. 1 in that it is not screwed into an internal thread of the housing 1, but rather onto an external thread of the housing. Only a single supply line 14 runs in the shaft part of the housing, which feeds both the nozzles 32 on the front of the head part and the bore 30 in the tool 29 via a ring line 14b. The exemplary embodiment shown in FIG. 9 is also particularly suitable for an angle piece with a turbine drive. It differs from the angle piece shown in FIG. 1 essentially by a lower part 16 of the push button 16 which is more solid in the outer area and which has no plastic extension on its underside, but instead a separate housing-fixed guide 40 for the metal tube 28 The nozzle 32 provided for the external cooling of the tool 29 as well as the bore 30 of the tool are fed with cooling liquid via a common supply line 14 which branches in the shaft part 2.

The angle piece shown in FIGS. 10 to 12 has a supply line 40 for compressed air, which opens into a semi-annular space 41 in the head part 3 close to its front side. A branch line 42 leads from the room 41 upwards into the lower part 16 of the push button and opens there into a central annular space 43 which surrounds the outlet 44 and is closed off by the central extension 24 of the upper part 17. The annular gap 28a opens into this annular space 43 and can thereby be pressurized from the outside in order to prevent any leakage.

The feed line 14 for water likewise leads into a half-ring space 45 at the tip of the head part 3; from there, a branch line 46 leads into the push-button lower part 16. A metal sleeve 47 is inserted into the clamping device 6, which leads to the underside of the upper part 17 and in turn receives a sleeve-shaped extension 48 of the upper part 17, forming the sealing gap 28a.

Claims

Claim:

1. Elbow for dental needs

with a housing (1) which consists of a head part (3) and a shaft part (2),

with a rotatably driven clamping device (6) accommodated in the head part (3) for clamping a drilling, milling or grinding tool (29) which is inserted into the clamping device (6) from the front of the head part (3) and has a longitudinally continuous bore (30),

with a push button (15) provided on the back of the head rope (3), which acts directly or indirectly on the tensioning device (6) and opens it against spring force when the push button (15) is depressed,

and with a feed line (14, 14a, 19, 20, 23) running in the shaft part (2) and head part (3) for a cooling fluid, which leads through the push button (15) and from behind into the bore (30) of the Tool (29) opens, for which purpose the push button (15) has an extension which protrudes into a sleeve (27) of the clamping device (6), forming an annular gap (28a), characterized in that the push button (15) consists of an upper part (17) which closes the rear of the head part (3) tightly, which is reversibly deformable by a membrane region (26), and a lower part (16) which forms the Clamping device (6) containing the interior of the head part (3) closes towards the rear, the feed line (20, 23) through the lower part (16) into the intermediate space (23) between the lower part (16) and the upper part (17 ) is guided and leaves this intermediate space (23) through an outlet (44) provided in the center of the lower part (16) and in the vicinity of this outlet (44) the upper part (17) has one or more extensions (24 ) which, on the one hand, keep the connection from the intermediate space (23) to the outlet (44) open and, on the other hand, are either supported on the lower part (16) and reversibly deflect it when pressure is exerted on the upper part (17) or as part of the supply line (23, 30) forming egg nes sealing gap (28a) engages through the outlet (44).

2. Angle piece according to claim 1, characterized in that the push button (15) in the alignment of the clamping device (6) has a hollow extension (27, 28) extending into the bore (30) of the tool (29).

3. Angle piece according to claim 2, characterized in that the tool (29) is drilled out from behind to a larger diameter than at the front, so that the flow cross section through the extension (27) and the tool (29) remains the same.

4. Angle piece according to claim 2 or 3, characterized gekenn¬ characterized in that the extension (27) at its tip has a bead (27b), the outer diameter is worked to fit with the bore (30) in the tool (29).

5. Angle piece according to one of the preceding claims, characterized in that the push button (15) has a hollow extension (27) which receives the rear end of the tool (30).

6. Angle piece according to claim 5, characterized in that at the rear end of the tool (29) on the outside an undercut (37) is provided, in which a matching, on the inside of the extension (27) formed projection (38) engages, so that the extension (27) tightly surrounds the tool (29).

7. Angle piece according to one of claims 2 to 6, characterized in that in the longitudinal direction of the extension

(27) there is play between this and the tool (29).

8. Angle piece according to one of the preceding claims, da¬ characterized in that the push button (15) consists of thermoplastic material.

9. Angle piece according to claim 8, characterized in that a projecting metal tube (28) is inserted into the rest of the plastic (27).

10. Angle piece according to one of the preceding claims, characterized in that the feed line (20) passes through the edge region of the lower part (16).

11. Angle piece according to claim 10, characterized in that between the lower part (16) of the push button and the housing (1) of the angle piece, an annular channel (19) is seen, which is part of the supply line.

12. Angle piece according to one of the preceding claims, characterized in that one or more nozzles (32) for external cooling of the tool (30) are arranged on the front of the head part (3).

13. Angle piece according to claim 12, characterized in that the nozzles (32) are supplied with cooling fluid in the angle piece by a separate, separately lockable supply line (45, 45a).

14. Angle piece according to claim 12, characterized in that the nozzles (32) and the hollow ^" tool (29) are fed by a common feed line (14) branching in the angle piece.

15. Angled piece with a compressed air supply line (40) leading into the head part (3) according to one of the preceding claims, characterized in that a compressed air branch line (42) leads to the outside of the annular gap (28a).

16. Angle piece according to one of claims 1 to 14, characterized in that the supply section between

Push button (15) and tool (29) is designed as a jet pump, the suction side of which is connected to the annular gap (28a).